Electric starter motors are commonly used to start internal combustion engines including gasoline and diesel powered engines. The electric starter includes a motor, an electromagnetic switch, and an auxiliary switch, and initiates rotation of a flywheel of the engine sufficient to enable the engine to run under the combustion power resulting from ignition of a gasoline or a diesel fuel.
The electric starter motor includes an electric motor which can be either a permanent-magnet or a series-parallel wound direct current electric motor which is electrically coupled to a vehicle battery through an electromagnetic switch, known as a starter solenoid. When current from the battery is applied to the electromagnetic switch either through turning of a key or by pressing a start button, current is applied to the electric motor. Upon energization, the solenoid engages a lever that pushes a drive pinion on a driveshaft of a starter driveshaft to engage the flywheel of the engine. Thus, rotational torque of the electric motor is transferred to the engine through the pinion to thereby start up the engine.
To smoothly start up the engine, a rotational torque of the electric motor is transferred to a drive pinion gear after the drive pinion gear engages the flywheel of the engine. In addition, once the engine has reached an operating speed, the pinion gear must be disengaged from the flywheel. Consequently, the operation of electric motor, and in particular the engagement of the pinion gear with the flywheel, should be synchronized with the engine to properly engage and disengage the flywheel.
To provide for proper synchronization, the engine starter also includes an auxiliary switch. Upon turning of the key or pressing of the starter button, the magnetic coil in the electromagnetic switch is energized. In response, a plunger is driven and the auxiliary switch is closed by the plunger. Consequently, a limited amount of current is supplied to the electric motor, thereby driving the electric motor to at a low number of revolutions per minute. The pinion gear then engages the flywheel. As the plunger is driven further, the electromagnetic switch is closed, and a larger amount of electric current is supplied to the electric motor to increase the number of revolutions per minute. The pinion gear engaging the flywheel is then driven by the electric motor to provide sufficient torque to turn the flywheel such that the engine starts and can continue operation from internal combustion in the engine.
Because the electric starter is mechanically and directly linked to the engine flywheel, the electric starter is placed in close proximity to the engine within the engine compartment. In addition, since the starter not only includes the motor, the electromagnetic switch, and the auxiliary switch, but also a housing to support the various components, the space requirements with respect to the arrangement of the various components should be considered. In particular, the amount of space available within an engine compartment is often limited. What is needed therefore is a system, mechanism, or structure by which the starter is configured to be properly located with respect to the engine to provide an electrical and mechanical advantage. In addition, because space is at a premium in an engine compartment, the location of the individual components of a starter should provide for the advantageous location of the starter within a variety of different sizes and shapes of engine compartments and also to provide for ease of access to the various components if one or more of the components requires a replacement or repair in case of a failure.